They don’t shamble in a malevolent sleepwalk, like the creatures in George Romero’s Night of the Living Dead. They aren’t adorable if voracious teens, like the undead kid in the ghoul-meets-girl Warm Bodies. The zombies in World War Z are a swift, teeming mass, a “perfect delivery system” for worldwide plague. They sprout on Philadelphia streets within a dozen seconds of being infected, career en masse off a Newark tenement rooftop in pursuit of fresh hosts. In Jerusalem, by the thousands, they climb over one another like huge, mad rats to scale a high wall and gnaw their virus into the refugees on the other side. Zombies — the military calls them “zekes” — have swarmed across the planet, killing billions, by the time ex–United Nations troubleshooter Gerry Lane gets involved. What chance does one man have to defeat a ravenous über-Army? Well, he’s played by Brad Pitt.

Max Brooks’ 2006 novel posed as an “oral history” of the Zombie War. Fictionalizing the interview techniques of Studs Terkel, the author (the son of Mel Brooks and Anne Bancroft) created a global docudrama of pandemic plague, government inefficiency, corporate crime and human fear. Part geopolitical satire, the book hopscotches among a dozen or so countries and includes more than 40 narrators offering their testimony to an unnamed U.N. employee. How could a story with so many perspectives and a corrosive view of greed under pressure become a big-budget Hollywood movie? Well, the producer was Brad Pitt.

A few years before he outbid Leonardo DiCaprio for the movie rights to World War Z and chose Marc Forster (Finding Neverland, Quantum of Solace) to direct it, Pitt had begun trying to make a film of another “unfilmable” book: Moneyball, Michael Lewis’ chronicle of how Oakland A’s general manager Billy Beane guided his underfunded team through the 2002 season. To Lewis’ already romanticized take on Beane and his sabermetric savvy, Pitt added a daddy-daughter subplot. Three different writers and three more directors later, the star-producer-philanthropist-dreamboat (and serial father) had birthed one of the most admired and likable movies of 2011.

Moneyball, at least, had a central, Pitt-friendly character to play. The synoptic structure of World War Z is more like the star’s Babel times about a billion. So Pitt and his never-ending platoon of screenwriters confronted a familiar Hollywood dilemma: How can we take an original, borderline-unique idea and change it so it resembles a bunch of other popular movies? The first writer he hired, J. Michael Straczynski (Changeling, Thor, the sci-fi TV series Babylon 5), invented Gerry Lane, a solitary hero charged with saving the world more or less on his own. Matthew Michael Carnahan (The Kingdom, Lions for Lambs, State of Play) fleshed out Gerry’s family — make ‘em nice, put ‘em in peril — and his search for the Patient Zero who might lead to the source of the zombie plague and its possible antidote. When shooting a version of the climactic all-out battle in the Brooks book proved unsatisfactory, Damon Lindelof (Lost, Prometheus, Cowboys & Aliens) conceived a new climax, which was rewritten by Drew Goddard (Lost, Cloverfield, The Cabin in the Woods).

Streamlining narrative sprawl into narrative drive isn’t the only challenge a would-be blockbuster faces. Aiming for a PG-13 rating deprived World War Z of the gross-out feeding scenes zombie fans love. Appeasing the huge foreign market of China meant removing references to the plague being discovered there and the government’s lying about it. The ambition to make this what Forster hopefully called the first film in a trilogy implied further compromises with the source novel. Because of the third-act reshooting and other problems, dissected in a recent Vanity Fair story, the movie’s budget ballooned from $125 million to more than $200 million, and its release postponed from last December to this week.

So they spent a bundle. Doesn’t matter; it’s not your money. Your ticket to this movie (unless you see the 3-D version) costs the same as one for a pinchpenny indie film like Much Ado About Nothing. And the movie isn’t the book. That’s okay too. Brooks’ volume wasn’t suppressed; it’s still available everywhere, and by reading it you can imagine your own perfect movie adaptation. As for the battle scenes that ended the film’s rough cut, I hope they’re in the inevitable DVD boxed set, along with commentary from Pitt and all the off-screen participants. If not, maybe Brooks could compile an oral history of the making of World War Z.

And here’s the oddest element in this tale of Hollywood fine-tuning run rampant: the movie is pretty good — the summer’s most urgent, highest-IQ action picture. The movie hurtles authoritatively from Philly to Newark to an aircraft carrier in the Atlantic to South Korea to Israel to Wales, like Richard Engel on a worldwide assignment. And on the personal side, Gerry’s relationship with his wife (Mireille Enos of Big Love and The Killing) and two young daughters (Sterling Jerins and Abigail Hargrove) shows all the care and concern — and the sensible sense of humor — that one would like to think Pitt lavishes on his own large family. It’s a smarter, more organic display of affection than the daddy-love scenes in Moneyball, as well an antidote to the stern father Pitt played in The Tree of Life. Then the primacy of Gerry’s wife and kids is tempered when a military officer warns him, “Don’t pretend your family is exempt when we talk about the end of humanity.” The good father is reminded that families around the world need the remedy he is trying to find.

Pitt, who will be 50 in December, has said of prolonged movie stardom, “One thing that sucks, your face kind of goes.” Not for him, not yet. His face is still there, and the rest of him, and it all looks great. More important, he exudes the intellectual rigor and emotional vigor of the engaged, humane liberal — the most photogenic approximation of the American Hero, plucked into a future war from a distant age when the country’s good deeds derived not from motives of revenge or profit but from a compulsion to help those unable to help themselves.

Though obviously indebted to Night of the Living Dead and the vast library of zombie literature, Pitt’s World War Z shares more with movies about epidemics, from the 1938 Yellow Jack (yellow fever) through Panic in the Streets, La Jetée (and the Terry Gilliam remake 12 Monkeys), The Birds, The Andromeda Strain, Children of Men, The Happening and Contagion. It’s as much about “Where did they come from?” as “When will they eat me?” Gerry is a descendant of the disease detectives in many of those films. When he arrives on the case, zombies already outnumber the surviving humans, and the U.S. President is one of their victims. (Quiz a Tea Party member on his feelings about that and he might say, “Mixed.”)

SPOILERISH PARAGRAPH: Leaving his family on the aircraft carrier, he ventures into infested areas, dodging zombie attacks along with a few script implausibilities, such as not notifying the Israeli authorities in charge of a chattering refugee population that the creatures respond to noise and, while tiptoeing through a horde of the infected, hearing his cell phone ringing. (Note to wife: Never call me at work!) Gerry also seems to think that the way to escape zombies on a plane is by shooting a hole in its side. The final 20 minutes, the part dreamed up by Lindelof, does put Gerry face-to-face with the previously undifferentiated enemy (played by a sniffing, growling Michael Jenn), but it’s a timid conclusion to the boldness of the earlier sections, referencing both the old-dark-house horror cliché and the confrontational cackling of such old avant-garde stage ensembles as the Living Theater. END OF SPOILERISHNESS.

For the most part, though, Forster’s docudrama approach is brisk, muscular and scary. Those zombie attacks (shot by ace cinematographer Robert Richardson) have the immediacy of otherworldly war footage, or a microscopic closeup of spreading bacteria, except that these germs used to be human. The movie hurtles authoritatively all over the globe, introducing characters the viewer wants to know more about — a Hispanic family, a tough Army dude (James Badge Dale), a scholar on zombies (Ludi Boeken), a renegade CIA operative (David Morse) — before it rushes off with Gerry as he finds a new area of plague or promise. Only Daniella Kertesz, as an Israeli soldier Gerry brings along for the ride, gets more than a minute or two of screen time.

The odd triumph of the World War Z movie is that it leaves you wanting to linger in its depiction of atrocity, because that’s where the movie’s great skill and drama reside. All-out zombie war is hell, but — as long as the person sitting next to you doesn’t carry the plague — it’s a wonder to watch.

I just watched it at noon, and its a really well done film. They did leave out specifics about China and the clash between Iran and Pakistan, but if you have read the book, the movie does very well at referencing and giving big nods toward those incidents. It really is a smart, well done film. And from what I've heard the 1st of a trilogy. I simply recommend it, if you don't like it, then ya don't like it LOL.

If this is the highest IQ of the summer, then the bar must be extremely low. This will give Will Smith a run for the bottom. Just saw this bomb and must wonder why Pitt ever took the role. Except for the CGI, this makes most B-level horror flicks look good.